1. Field of the Invention
The invention relates generally to an electrocardiograph leadwire assembly, and more specifically to an electrocardiograph leadwire assembly which enables convenient and safe implementation of a variety of leadwire number and positioning configurations in a durable, quickly accessible and adaptable, compact, easily storable, and safe assembly.
2. Background of the Invention
A heart beats as the result of electrical activity occurring within its individual cells. These small electric forces are conducted throughout the body and can be measured at the body's surface and studied. Electrocardiography, the study of these cardiac electrical signals, provides the clinician with valuable information on a patient's cardiac status. It can allow for the early detection, and thus treatment, of such cardiac disorders as dysrhythmias, conduction abnormalities, myocardial ischemia/infarction, and adverse drug and electrolyte effects.
An electrocardiograph is an instrument that detects the cardiac electrical activity at the body's surface, then processes and displays this information to produce a visible record. The device continuously monitors the voltage differences between at least two body surface electrodes over time, and records them to create a curve called an electrocardiogram (ECG). The ECG is thus a continuous voltage-time record which can provide essentially "real-time" information about cardiac electrical activity.
More specifically, the voltage differences are detected by means of a number of conductive electrodes placed on the body surface. Each of the electrodes is connected to the electrocardiograph unit by a leadwire. A continuously varying difference in voltage between at least two electrodes is measured and displayed. This continuously varying voltage difference between at least two electrodes, occupying at least two different positions in the heart's electric field is called a "lead". This is in contradistinction to a "leadwire", which is the wire that actually carries the electric current. A lead therefore will assume different configurations depending upon the location of the electrodes being evaluated.
The monitored cardiac electrical activity can be presented in several forms. Most electrocardiographs will display the ECG in "real-time" on a video display-monitor, as well as record a tracing of the curve on graded strip paper. Generally, the device will display one to three ECG leads simultaneously on the video-display monitor, with the video-display lead(s) chosen by means of a channel select.
There are three primary ECG configurations in clinical use today. These configurations allow the monitoring of from 1 to 12 leads and require either 3, 5, or 10 leadwires, connected with the electrocardiograph unit and extending to the patient. The most complete type of ECG monitors 12 leads, from 10 electrodes placed at 10 standard locations on the patient's 8 body, and thus produces 12 different voltage-time graphs. Some leads are more "sensitive" than others in detecting certain abnormalities, with different leads and lead combinations providing better "views" of different aspects of the heart's electrical activity. Furthermore, sensitivity and diagnostic capability are generally increased by monitoring more than one lead, such that the combination of multiple leads provides a more complete picture of the heart's activities. However, because different clinical situations require different types and amounts of information, a clinician may generally wish to tailor the number and configuration of leads being employed to the particular application.
The conventional, non-retractable ECG wires commonly used today have certain problems and limitations. For example, ECG leadwires, due to their length and current design, create a storage problem when not in use. As a result, clinicians often struggle to find out-of-the-way locations in which to maintain the wires. Unfortunately, however, the leadwire assembly is often hung from intravenous ("IV") poles, the ECG monitoring unit or various other medical equipment, or is curled into a bundle and rested on a flat surface. When stored in this manner, the leadwires are easily displaced and/or tangled, take up much space, and are susceptible to damage. Furthermore, it can be hazardous to have long wires strewn about an often crowded monitoring environment, such as an operating room ("O.R.") or ambulance.
Tangling of leadwires is an extremely common problem. All the leadwires, and particularly the longer limb leadwires, tend to become easily tangled among themselves and other objects. Accordingly, when these wires need to be used, a clinician must frequently struggle to untangle them. This is not only frustrating and time-consuming, but potentially dangerous when immediate monitoring is needed or the clinician's time and attention should be directed elsewhere.
Another important problem associated with electrocardiograph leadwires and their manner of storage relates to damage. Hospitals, in particular, contain a great deal of heavy equipment, much of it mobile and in confined areas where people quickly move around. The electrocardiograph unit itself is often mobile. If the leadwires are carelessly positioned they can become kinked, entangled with and/or run over by people and heavy equipment. The type of damage that results is often difficult to detect and can arise over time. Accordingly, untimely malfunctions and/or unreliable ECG signals can result when the electrocardiograph is being relied on to provide accurate and critical cardiac monitoring.
In addition, clinical situations change quickly and unexpectedly. A clinician often cannot anticipate which particular ECG configuration will be required until a specific medical circumstance arises and the needs of the patient can be assessed. Therefore a situation can arise in which a clinician, after having already begun a procedure or treatment using a "three-lead" monitoring configuration, wishes to monitor additional leads because of an unanticipated development. It is time consuming and often not feasible to change to another device containing more leadwires. The clinician's diagnostic capability is therefore limited by the inflexibility of the present ECG device.
Thus, there is a substantial need in the art relating to electrocardiographs to provide an electrocardiograph leadwire assembly which allows its leadwires to be protected and stored out of the way when not in use. Such a device would increase the life and long-term accuracy of the electrocardiograph and would also eliminate a source of hazard often present in most monitoring environments. Furthermore, there is a need for an electrocardiograph leadwire assembly which will not require a substantial amount of a clinician's time and attention to untangle, locate, or otherwise implement. There is also a need for an electrocardiograph leadwire assembly which will allow for a varying number of leadwires to be used, so as to accommodate a variety of monitoring configurations, while leaving the remaining leadwires protected.